ARM: __io abuse cleanup

Several platforms incorrectly use __io() for casting to 'void __iomem *'.
This converts all of those uses to use the common IOMEM macro.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-sh@vger.kernel.org
Acked-by: Arnd Bergmann <arnd@arndb.de>